In the office environment, it is often desirable to provide a machine which can function to sort the output from a copier or printer into trays to which the sheets may be serially fed for collation or randomly fed for mailboxing, or in the case of digital copying or printing, for receiving the sets in collated fashion.
Typically, sorting mailbox machines may be provided with fixed receiving trays to which the sheets are supplied either serially or randomly for mailboxing purposes, as for example, shown in my prior U.S. Pat. No. 5,938,194 granted Aug. 17, 1999 and other prior art patents, which, in a generic sense, function to receive sheets of paper fed from the printer or copier to a moving inlet feed path which is vertically displacable or to a feed path which includes gates for deflecting sheets from the feed mechanism into the trays.
On the other hand, as represented by Lawrence U.S. Pat. No. 4,843,434 granted Jun. 27, 1989, the sheets may be fed to trays which are opened by a moving bin opener which may be vertically positioned to open a selected tray and the infeed moves with the bin opener.
Various other examples of sheet receiving, sorting or mailboxing machines are known for selectively receiving the output from the sheet printing or copying apparatus. Canon U.S. Pat. No. 5,385,340 granted Jan. 31, 1995 and Lawrence U.S. Pat. No. 5,649,695 granted Jul. 22, 1997 disclose examples of paper receiving or stacking devices which assemble and finish a stapled set of sheets by means which in a preliminary stage, assembles the trailing ends of the sheets on a shelf while the leading ends of the sheet are otherwise supported.
In the Canon structure, the set of sheets is supported at its trailing end on a fixed shelf from which the assembled set is pushed to a receiver.
In the Lawrence structure, the assembled set of sheets is gripped and moved to a finishing station after accumulation of the trailing ends of the sets on a movable shelf.
My pending application, Ser. No. 078,202, filed May 14, 1998 is co-owned herewith and discloses a stacker with which are associated a binding station and a stapling station. In that application there is also disclosed a shelf which receives the trailing ends of sheets being accumulated for processing at either of the binding or stapling stations, wherein the shelf is allowed to pivot downwardly to drop the trailing ends of the accumulated set of sheets.
In my pending application, Ser. No. 280,599, filed Mar. 29, 1999, co-owned herewith, there is disclosed a stapling stacker in which the trailing ends of the sheets fed through are supported on an L-shaped shelf, while the leading ends of the sheets are supported on a previously stacked set, wherein the sets are side edge aligned, stapled and offset with respect to previously stapled sets, and the shelf is then pivotally dumped to deposit the set on the stacker or on the previously stacked sets.
None of these prior patents addresses the need for being able to finish or staple the sets in an apparatus of the type in which the receiving trays are vertically movable past a sheet inlet by operating cam structures as illustrated for example, in my prior U.S. Pat. No. 5,255,902 granted Oct. 26, 1993. In this patent, a set of trays can be successively moved upwardly or downwardly by means including a pair of spiral cams rotatable by a pair of shafts. As is well known, if the cams are controlled to be rotated in a selected direction at selected times, the trays will function to receive sets of sheets in addressed fashion, i.e., as a mailbox.